System and method for delivering expanding trocar through a sheath

ABSTRACT

A trocar has an elongate body and a tissue-penetrating tip. One or more radially extending blade(s) are provided near the tissue-penetrating tip of the trocar body so that they automatically open as the trocar is advanced through tissue. The blades will enlarge the penetration which was formed by the tip of the trocar.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of priority of U.S. ProvisionalPatent Application No. 61/171,228 (Attorney Docket No. 026923-001200US),filed on Apr. 21, 2009, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical apparatus andmethods. In particular, the present invention relates to a penetrationdevice, such as a trocar, having the ability to expand the size of atissue penetration as the tool is advanced.

A number of endoscopic and other intraluminal procedures requirepenetration from one body lumen into an adjacent body lumen. Forexample, a number of procedures may be performed by entering thegastrointestinal (GI) tract, particularly the stomach, duodenum, smallintestine and large intestine, and passing tools from the GI tract intoadjacent organs, ducts, cavities and structures, such as the bile duct,the pancreatic duct, the gallbladder, urinary tract, a cyst orpseudocyst, abscess , and the like. Since the endoscopes and otherendoscopic access tools are generally small with narrow workingchannels, typically 2 to 7 millimeters in diameter, any penetratingtools which are advanced through such working channels will necessarilybe small and provide for only small tissue penetrations.

Depending on the procedure being performed, it is often desirable toplace a catheter, a stent, a drainage tube, a fiducial marker implant,an electrode or a like second diagnostic or therapeutic device, throughthe penetrations that have been formed. Often, placement of such toolsand implants requires a relatively large diameter hole to allowsubsequent passage of the second device. In many cases the desireddiameter of the second device is larger than the maximum diameter of thepenetrating member and the insertion of the second device is oftendifficult. Commonly, the lumen walls include muscle layers andsignificant force is required to advance the catheter from one lumen tothe next. Such advancement can be more difficult and may fail if thesize of the penetrating element is increased in order to provide alarger penetration.

For these reasons, it would be desirable to provide trocars or othertissue-penetrating devices which can be used intraluminally to penetratefrom one body lumen into an adjacent lumen where the size of thepenetration can easily be enlarged. In particular, it would be desirableto provide such tools and methods where a relatively low force is neededto advance the tool through the tissue while still achieving arelatively large penetration. Such tools and methods should becompatible with standard endoscopes and other sheaths which can be usedto access a target location in the gastrointestinal tract or other bodylumen. At least some of these objectives will be met by the inventionsdescribed hereinbelow.

2. Description of the Background Art

Trocars and other medical access devices having deployable cuttingblades are described in U.S. Pat. Nos. 5,372,588; 5,620,456; 6,402,770;7,429,264; and US 2008/0045989. Other disclosures of interest are foundin U.S. Pat. Nos. 5,224,945; 5,697,944; 6,371,964; 7,303,531; and US2006/0190021.

BRIEF SUMMARY OF THE INVENTION

The present invention provides improved trocars and othertissue-penetrating devices which can be used with endoscopes and otherviewing scopes and sheaths. The trocars can be advanced from a workingchannel or other lumen or passage of the sheath and penetrated throughan adjacent luminal wall and, typically, further into and through thewall of an adjacent body structure or organ. Thus, the trocars areparticularly useful for providing intraluminal access from one bodylumen or cavity into an adjacent body lumen or cavity. The trocars willmost often be used for forming penetrations and passages from agastrointestinal structure, such as the esophagus, the stomach, theduodenum, the small intestine, and the large intestine, into an adjacentstructure or organ, such as the bile duct, the pancreatic duct, thegallbladder, the urinary tract, a cyst or pseudocyst, an abscess, andthe like. The trocars of the present invention are useful in any medicalprocedure where an elongate, flexible tool is advanced through an accesssheath to a remote location in order to penetrate tissue.

Trocars according to the present invention are intended for use with acatheter, endoscope, or delivery sheath having a working channel orother lumen. Such trocars usually comprise an elongate body which can beadvanced through the sheath working channel or lumen, typically having aflexible body with a stiffness typical for standard endoscopic biopsyneedles. At least one blade will be disposed near a distal end of theelongate body where the blade is biased to open from a radiallyretracted configuration to a radially extended configuration. Inparticular, the blade will be radially retracted when the distal end ofthe elongate body is disposed within the sheath lumen, and the bladewill open radially when the distal end is advanced distally beyond theend of the sheath lumen. Usually, the blade(s) will be adapted to closeradially in response to being drawn back into the sheath lumen. In thisway, the trocar body can have a relatively small width or diameter,typically in the range from 0.4 mm to 5 mm, while the extended bladescan significantly increase the size of the tissue penetration which isformed when the distal end of the trocar is advanced through tissue.Moreover, as the blade is biased to open as the distal end of the trocaris extended beyond the working channel of the sheath, there is no needfor the physician to separately actuate the blade and instead the largercutting size is automatically provided as the penetration is beingperformed.

Usually, at least a portion of the forward edge or surface of the bladewill be sharpened or otherwise adapted so that it can penetrate tissue.Typically, conventional honing or other physical modification of theblade will be sufficient to provide the cutting surface. Alternatively,electrodes or other electrosurgical carriers, wires, metalized surfaces,or the like, may be provided on the blade in order to enhance thecutting effect when connected to a suitable electrosurgical powersupply. In contrast, the trailing or proximal side of the blade willusually be blunt or atraumatic in order to avoid accidental cutting ortissue trauma when the trocar is pulled back. A blunt trailing edge isfurther desirable when the blade is configured to close as it is drawnproximally to engage a leading edge of the working channel of theendoscope or sheath.

In other embodiments, the blade can be configured to be actively closedby the physician after the tissue penetration is complete. For example,a tether or other structure for pulling the blade back to close theblade against the bias may be provided.

In most embodiments, the elongate body of the trocar will also have afixed tissue-penetrating element at its distal tip to permit orfacilitate advancement through tissue. The tissue-penetrating tip maycomprise a sharpened tip, a chamfered tip, an electrosurgical tip, orany other common tip or modification which allows the body to beadvanced forwardly to penetrate tissue. In other embodiments, however,it may be possible to provide a body having a blunt or atraumatic tipwhere the deployed blade provides the entire cutting surface for thetrocar.

In some embodiments, the trocar will include only a single blade whichis pivotally mounted so that opposite ends of the blade rotate to openfrom opposite sides of the elongate body. Such embodiments may be biasedusing a coiled spring disposed about an axis or pivot point of theblade. Such rotating single blades can be used together with a tetherfor tensioning the blade to rotate and collapse or otherwise close theblade back into the elongate body. Alternatively, the blade and sheathcan be configured such that drawing the trocar proximally back into thesheath automatically retracts the blade.

In other embodiments, the trocar may comprise at least two biased bladesattached to a single pivot point to open in a scissors-like patternwhere each of the blades has a sharpened distal edge to cut tissue asthe elongate body is advanced. In still other embodiments, two biasedblades may be attached to pivot points on opposite sides of the elongatebody where the blades are parallel to each other when retracted withinthe elongate body. In further embodiments, two blades may be attached ataxially spaced-apart locations on the elongate body and/or inrotationally spaced apart locations. In addition to planar blades, theblades may comprise pre-shaped wires or other shape-memory componentswhich radially expand outwardly when released from constraint. In suchcases, the wires are typically not pivoted in any way. In still otherembodiments, the blades may be conformed circumferentially over thesurface of the elongate body and attached with an axial line hinge withsprings to radially open or unfold the blades.

The present invention further provides methods for accessing internalbody organs. The methods of the present invention comprise introducing adelivery sheath through the working channel of an endoscope to alocation adjacent to a target location on a wall of an organ or lumen. Atrocar is then advanced from a lumen in the delivery sheath so that thetrocar penetrates the organ or lumen wall at the target location. As thetrocar is advanced, a blade is released from constraint so that theblade opens radially as the trocar exits the lumen. The released,expanded blade may thus enlarge the penetration which was made by thedistal tip of the trocar as it was advanced. In many cases, theendoscope, viewing scope, or other delivery sheath from which the trocarwas advanced will be introduced through a natural body orifice, such asthe mouth, anus, ureter, and/or vagina and cervix, allowing for theperformance of a natural-orifice translumenal endoscopic surgery (NOTES)which avoids the need to form a percutaneous tissue penetration. Inaddition, translumenal interventional endoscopy procedures can beaccomplished including transoral or transanal access of a cyst,pseudocyst or abscess for drainage into the GI tract, transoral ortransanal access of the gallbladder, bile duct and pancreatic duct fordrainage into the GI tract, transoral access of the heart from theesophagus for delivery of drugs, placement of electrodes, and ablationof tissue , transoral access of the pancreas, gallbladder, kidneys,liver, spleen and any other organs or structure adjacent to the GI lumento deliver fiducial markers, drugs, and tissue ablation from the GItract.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a trocar having an extendable blade constructed inaccordance with the principles of the present invention.

FIGS. 2 and 2A illustrates a first particular construction of theactuable blade of the trocar of the present invention.

FIG. 3 illustrates a second particular embodiment of an actuable bladeconstructed in accordance with the principles of the present invention.

FIGS. 4A and 4B illustrate yet another embodiment of the actuable blademechanism of the trocars of the present invention, where FIG. 4A is across-sectional view of a distal section of the trocar and FIG. 4B is anend view of the distal section.

FIGS. 5A-5C are similar to FIGS. 4A and 4B, except that the bladestructure has been actuated by advancing the trocar out the distal endof a constraining sheath.

FIGS. 6A and 6B illustrate a blade assembly where three blades areaxially hinged in order to open in a radial or petal pattern.

FIGS. 7A and 7B illustrate a deformable wire blade structure on a trocaraccording to the present invention.

FIGS. 8A and 8B illustrate axially and radially spaced-apart blades on atrocar in accordance with the principles of the present invention.

FIGS. 9A to 9C illustrate a single asymmetric blade embodiment of thetrocar of the present invention.

FIGS. 10A-10D illustrate use of the trocar of FIGS. 4A/B and 5A/B forpenetrating a tissue wall in accordance with the principles of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a trocar 10 constructed in accordance with theprinciples of the present invention comprises an elongate body 12 havinga distal end 14 and a proximal end 16. An actuable blade structure 18 isdisposed near the distal end 14 of elongate body 12, where the blade isshown in a radially expanded configuration in broken line.

The length and dimensions of the elongate body 12 will depend on theintended use of the trocar. Typically for gastrointestinal procedures,elongate body 12 of the trocar will be sized to be introduced through anendoscope and will have a length in the range from 50 cm to 500 cm and awidth or diameter in the range from 0.4 mm to 5 mm. The elongate bodymay be a solid wire or have a hollow structure with an axial passage orlumen. The body may be formed from polymers, such aspolytetrafluoroethylene (PTFE), nylon, poly(ether ether ketone) (PEEK)or polyethyleneterephthalate (PET), or metals, such as stainless steel,elgiloy, or nitinol. In certain instances, it may be desirable toreinforce the body with braid, helical wires, or other conventionalcomponents. In other cases, the body may be formed from differentmaterials over its proximal length and its distal length. For example,the proximal length may be formed from metal hypotube or wire while thedistal, more flexible portion is formed from a polymer tube, optionallya reinforced polymer tube. In other embodiments, the elongate body 12may be straight and relatively rigid over its entire length.

The elongate body 12 will usually have a tissue-penetrating tip 20 atits distal end, where the tip may be conical, chamfered,electrosurgical, or be provided in any conventional form for a trocar.For example, the tip might have a multi-faceted face with sharpenededges for penetrating, as is commonly employed with tissue-penetratingtrocars (as shown in FIGS. 9A and 9B).

Referring now to FIG. 2, a first embodiment of the blade assembly 18will be described. A single blade 24 is mounted within the elongate body12 on a pivot 26. A pair of opposed windows 28 allow the blade to rotateor pivot between an axially aligned configuration, as shown in brokenline, where the blade is fully refracted within the peripheral envelopeof the trocar, and a radially extended configuration shown in full linewhere a leading, cutting edge 30 of the blade is disposed toward thedistal end 14. The blade is biased by a coil spring 32 (a leaf or otherspring could also be used) which is attached at one end to the blade andthe other end to the fixed pivot so that, in the absence of constraint,the blade will open to its extended configuration as shown in full line.Thus, when constrained within a sheath or working channel or other lumenof an endoscope, the blade will be held in its retracted or constrainedconfiguration, as shown in broken line. When advanced from the sheath orworking channel, however, the spring 32 will automatically open theblade so that the cutting edge 30 is exposed to the tissue as the trocaris advanced. It is also possible for the spring to only partially openthe blade once the trocar is advanced from the sheath, the initialtissue interference of cutting edge 30 then causing the blade to fullyopen and penetrate through the tissue layers. After use, the blade canbe closed by pulling proximally on a tether 34 to close the blade downto its retracted (broken line) configuration.

Alternately the blade and constraining sheath can be configured suchthat proximal movement of the trocar into the constraining catheterresults in automatic retraction of the blade. In this instance, as shownin FIG. 2A, the lower rear edge of the blade 24′ has a protrusion 36that contacts the constraining catheter as the trocar is movedproximally relative to the sheath, thus rotating the blade against thespring force into the refracted configuration. A relief or cut out 38may also be formed on the upper rear edge of blade 24′ to prevent therear edge of the blade from interfering with the catheter as it isretracted. Alternatively, the upper rear edge of the blade may besharpened (in addition to or in place of the cut out 38). Drawing thetrocar into the constraining catheter or sheath causes the protrusion 36to contact the leading edge of the constraining catheter/sheath rotatingthe blade counter-clockwise (as seen in FIG. 2). The sharpened edge willcut any tissue that may be between it and the trocar, allowing it toretract fully.

Referring now to FIG. 3, a further embodiment of the blade structure 18includes a pair of opposed blades 40 and 42. Each of the blades 40, 42is mounted on a pivot 44 and 46, respectively, and includes a spring 48and 50 which will open the blade from the retracted or constrainedconfiguration shown in broken line to the extended configuration shownin full line. Each blade has a cutting edge 52 which is exposed totissue as the trocar 10 is advanced distally. The blades each have atether 34 to permit the blades to be retracted after use. Alternatelythese blades can be configured such that the tip of the retracted bladeis positioned distal to the pivot, requiring a proximal rotation of theblade into the extended orientation. In this configuration the trocarcan automatically retract as the trocar is pulled distally into therestraining catheter.

In the embodiments of both FIGS. 2 and 3, the blades will notautomatically retract as the trocar 10 is pulled back into a sheath orendoscope. Thus the tethers are needed to retract the blades prior topulling the trocars back into the sheath. In other embodiments, however,as described below, the blades will automatically retract as the trocaris pulled back into a sheath. The first such structure is illustrated inFIGS. 2A, 4A/B and 5A/B.

The trocar 10 of FIGS. 4A and 4B includes blades 60 and 62 mounted on asingle common pivot 64. Each blade has a coil spring 66 attached to theblade and pivot in order to open the blade, as shown in FIGS. 5A and 5B,in the absence of constraint. As shown in FIGS. 4A and 4B, the blades 60and 62 are constrained within a sheath 70 having a passage or channel 72through which the trocar can be advanced or retracted. So long as theblades 60 and 62 of the trocar 10 are within the lumen 72 of the sheath70, the blades remain constrained as shown in FIGS. 4A and 4B. Byadvancing the distal end 14 of the trocar further from the distalopening of the sheath 70, as shown in FIGS. 5A and 5B, the blades 60 and62 will automatically open under the spring bias so that leading cuttingedges 74 and 76 are exposed to tissue as the trocar is advancedtherethrough. In this embodiment, the blades will automatically retractand close as the trocar 10 is pulled back within the sheath 70 since thedistal end of the sheath will engage the back sides of the blades toclose the blades as they reenter the sheath. Leading cutting edges 74and 76 are shown being perpendicular to the axis of the trocar, howeverit may be desirable for cutting edges to be tapered or angled proximallyto enhance the ease of the puncture. In this case, the lateral most tipof the open blade is positioned proximal to the inboard tip of the bladeas shown in FIG. 5C (blades 60′ and 62′).

A variety of other biased blade constructions may be employed. Forexample, as shown in FIG. 6A and 6B, multiple blades 80 may be mountedon axially aligned pivots 82 so that the blades open or unfold in apetal-like manner as they rotate about the longitudinal axes of thepivots 82. Springs may be provided in order to unfold the blades 80 andtethers may be provided to close the blades.

In still further embodiments, the blades may comprise deformablestructures rather than pivoted structures. For example, as shown inFIGS. 7A and 7B, a plurality of wire blades 90 will be provided on theelongate body 12 of the trocar 10. The blades may be formed from aresilient material, such as spring stainless steel, Nitinol, or othershape memory materials, and may be heat set to have the open, cuttingconfiguration as shown in FIG. 7B. Thus, in the absence of constraint,the blades will “spring” to their extended cutting configuration. Theblades may be retracted by drawing them into the constraining sheath 92,shown in broken line in FIG. 7A.

Referring to FIGS. 8A and 8B, a plurality of blades may be provided in avariety of configurations. As seen in FIG. 8A, blades 100 and 102 may beaxially spaced-apart over the elongate body 12, while as shown in FIG.8B, the blades may be radially spaced-apart in configurations other than180° opposition.

A trocar 120 having a single, asymmetrically attached blade 122 isillustrated in FIGS. 9A-9C. The trocar 120 has a faceted tip 124 and atrough or recess 126 which receives the pivotally mounted blade 122. Theblade 122 will be biased, typically by a resilient structure such as acoil or leaf spring (not shown), to open at an angle greater than 90° sothat the blade is “swept back” as it is held by engaging the rear edgeof the recess 126. The blade 122 has a honed edge 128, as best seen inFIG. 9C, so that it will cut a wide incision through tissue as thetrocar is advanced. The blade 122 may be closed by refraction back intothe lumen or passage of the deployment sheath.

Referring now to FIGS. 10A-10D, use of the trocar 10 of FIGS. 4A/4B and5A/5B for penetrating a tissue layer TL will be described. Initially,trocar 10 is advanced to the tissue layer with the blades retractedwithin sheath 70 and the penetrating tip 20 of the trocar engagedagainst the tissue layer. The blades 60 and 62 extend radially as thetrocar 10 is advanced from the sheath 70, as shown in FIG. 10B. Thepenetrating tip 20 of the trocar will have entered the tissue as theblades extend and the cutting edges 74 and 76 engage the tissue. Thetrocar continues to be advanced through the tissue layer TL until itpasses out the other side, as shown in FIG. 10C. It can be seen that thepenetration P formed has a width which is much greater than would havebeen obtained using the trocar 10 without the blades 60 and 62. Beforewithdrawing the sheath 70, it can be advanced over the sheath to closethe blades, as shown in FIG. 10D, and the sheath can be pulled backthrough the penetration P without exposing the blades unintentionally.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention which is defined by the appendedclaims.

What is claimed is:
 1. A trocar for use with a delivery sheath having alumen, said trocar comprising: an elongate body which can be advancedthrough the sheath lumen; and at least one blade disposed near a distalend of the elongate body, said blade being biased to open from aradially retracted configuration to a radially extended configuration,wherein the blade is radially retracted when the distal end of theelongate body is within the sheath lumen and said blade opens radiallywhen the distal end is advanced distally beyond the sheath lumen.
 2. Atrocar as in claim 1, wherein the blade closes radially in response tobeing drawn back into the sheath lumen.
 3. A trocar as in claim 2,wherein the blade has a proximal surface which engages a distal surfaceof the delivery sheath to collapse the blade as the blade is drawnproximally back into the sheath lumen.
 4. A trocar as in claim 1,further comprising means for pulling the blade back into the elongatebody.
 5. A trocar as in claim 1, wherein said elongate body has atissue-penetrating distal tip.
 6. A trocar as in claim 5, wherein thetissue penetrating tip comprises a sharpened tip.
 7. A trocar as inclaim 1, wherein a single blade is pivotally mounted so that oppositeends of the blade rotate to open from opposite sides of the elongatebody.
 8. A trocar as in claim 7, further comprising a tether attached tothe blade, wherein the tether can be tensioned to collapse the bladeprior to drawing the blade back into the sheath.
 9. A trocar as in claim7, wherein the blade has a proximal surface which engages a distalsurface of the delivery sheath causing the blade to collapse as theblade is drawn proximally back into the sheath lumen.
 10. A trocar as inclaim 1, comprising at least two biased blades attached to a singlepivot to open in a scissors-like pattern wherein the blades havesharpened distal edges to cut tissue as the elongate body is advanced.11. A trocar as in claim 1, comprising two biased blades attached topivot points on opposite sides of the elongate body, wherein the bladesare parallel to each other within the elongate body.
 12. A trocar as inclaim 1, comprising two blades which are axially spaced-apart on theelongate body.
 13. A trocar as in claim 12, comprising three bladesaxially spaced-apart on the elongate body.
 14. A trocar as in claim 1,wherein the blade(s) comprise pre-shaped wires which expand radiallyoutwardly when released from constraint.
 15. A trocar as in claim 14,further comprising a tether attached to the wire, wherein the tether canbe tensioned to collapse the wire prior to drawing the trocar back intothe sheath.
 16. A trocar as in claim 1, wherein the blade is conformedcircumferentially over the surface of the elongate body, wherein theblade is attached with an axially aligned hinge.
 17. A method foraccessing an internal body organ, said method comprising: introducing adelivery sheath to a location adjacent to a wall of the organ; andadvancing a trocar from a lumen in the delivery sheath, wherein thetrocar penetrates the wall of the organ; wherein advancing the trocarreleases a blade from constraint within the delivery sheath lumen sothat the blade opens radially as the trocar exits the lumen such thatthe blade enlarges the penetration made by the distal tip of the trocar.18. A method as in claim 17, wherein the delivery sheath is introducedthrough a natural body orifice.
 19. A method as in claim 18, wherein thedelivery sheath is introduced transorally or transanally into the GItract to access a cyst, pseudocyst or abscess.
 20. A method as in claim18, wherein the delivery sheath is introduced transorally or transanallyinto the GI tract to access a gall bladder or a urinary bladder.
 21. Amethod as in claim 17, wherein the delivery sheath comprises anendoscope and the lumen comprises a working channel of the endoscope.22. A method as in claim 17, wherein the trocar has a tissue-penetratingtip and forms the penetration as it is advanced through the organ wall.23. A method as in claim 17, wherein the blade is biased to spring openas the constraint is removed.
 24. A method as in claim 17, wherein asingle blade opens.
 25. A method as in claim 17, wherein a pair oflaterally opposed blades open.
 26. A method as in claim 18, wherein thedelivery sheath is introduced transorally or transanally into the GItract to access the bile duct or pancreatic duct.
 27. A method as inclaim 18, wherein the delivery sheath is introduced transorally ortransanally into the GI tract to access an organ or structure in theabdominal, pelvic or thoracic cavity adjacent to the GI tract.
 28. Amethod as in claim 17, wherein the delivery sheath comprises a catheterwith a length from 20 cm to 500 cm and a diameter from 1 mm to 5 mm.